Up-Regulation of Intrarenal Renin-Agiotensin System Contributes to Renal Damage in High-Salt Induced Hypertension Rats

Abstract

Background/Aims: To investigate the change of intrarenal renin-agiotensin system (RAS) and its role in high-salt induced hypertension. Methods: Wistar rats were divided into normal-salt (NS), high-salt diet (HS) and high-salt diet with Losartan group (HS+L), for 6 weeks. Systolic blood pressure (SBP) was monitored. Blood and urine samples were collected every 2 weeks. Angiotensinogen (AGT) was measured by ELISA. AGT mRNA and protein were measured by real-time PCR and immunohistochemistry. Renin activity and angiotensin II (Ang II) were measured by radioimmunoassay. Results: HS versus NS group, SBP increased from 2nd week (Pth week (PP>0.05), renal cortex renin, AGT, and Ang II increased significantly in HS (PP>0.05) but abolished the increase of proteinuria (PPPP P Conclusion: Inappropriate response of the renal RAS to a high salt diet may contribute to hypertension and renal damage, and urinary AGT could reflect intrarenal RAS activity.

Keywords

• Hypertension
• Intrarenal RAS
• Angiotensinogen
• Angiotensin II
• High-salt diet